The newest emissary from Earth arrived at the Red Planet on March 10. The NASA craft, known as the Mars Reconnaissance Orbiter, joins three other satellites exploring the planet: two from NASA and one from the European Space Agency. Meanwhile, the twin rovers Spirit and Opportunity, more than 2 years after they landed, continue their treks along the Red Planet’s surface.
Using instruments ranging from radar sensors to gamma-ray detectors, Orbiter will explore the Martian atmosphere and surface and search for underground deposits of water. The craft’s highest-resolution camera will discern features as small as a card table. Orbiter will also scope out sites suitable for future landing missions and act as a communications relay for other craft, radioing data to Earth at 10 times the rate of any previous Mars craft.
The new arrival is currently in a highly elongated orbit. Over the next 6 months, engineers will command Orbiter to dip into the Martian atmosphere some 500 times to slow the craft and ease it into the smaller, circular orbit required for the main mission, which will begin in November.